Summary: Proc. Natl. Acad. Sci. USA
Vol. 90, pp. 118-122, January 1993
Neurobiology
Brain weight and life-span in primate species
JOHN ALLMAN, TODD MCLAUGHLIN, AND ATIYA HAKEEM
Division of Biology (216-76), California Institute of Technology, Pasadena, CA 91125
Communicated by Carver A. Mead, September 23, 1992
ABSTRACT In haplorhine primates (tarsiers, monkeys,
apes, and humans), there is a significant correlation between
brain weight and maximum life-span when the effect of body
size is removed. There is also a significant correlation in
haplorhine primates between brain weight and female age at
first reproduction. For strepsirhine primates (lorises and le-
murs), there are no significant correlations between brain
weight and either life-span orfemale reproductive age when the
effect of body size is removed. This lack of correlation in
strepsirhine primates may be related to the fact that these
primates are nocturnal and/or natives of the island of Mad-
agascar, both of which conditions may reduce competition for
resources and predation pressure. These rmdings suggest that